The evidence linking smoking with lung cancer is much less convincing than we are led to believe. For one thing, there is much disagreement about what the actual risk factor is.
The general consensus seems to reflect the pioneering studies of Professor Sir Richard Doll in the 1950s and 60s, which are still regarded as ‘benchmarks’. Doll reckoned that about 160 in 100,000 smokers developed lung cancer as opposed to 7 in 100,000 nonsmokers; so you have about a 24 times greater risk if you smoke. This can also be expressed as ‘2,400%’. But beware of estimates of ‘increased risk,’ especially when expressed in percentages; they’re a good sign that someone is trying to frighten, rather than to inform.
If you buy 25 lottery tickets instead of one, your chances of winning go up by 2,500%. But though the number sounds impressive, your actual chances of winning are still minuscule.
Likewise, if Prof Doll was right, you still have a 99.8% chance of not getting lung cancer. This is nothing more or less than a re-presentation, or re-packaging, of the same data. But it immediately sounds a lot less scary. Especially if smoking is something you love.